To avoid re-connection...

- If you have to access to a server behind a firewall and the session often expires:

reset by

peer

Connection to 1.2.3.4 closed

Modify /proc/sys/net/ipv4/tcp_keepalive_time this way:

echo "60" > /proc/sys/net/ipv4/tcp_keepalive_time

Your machine sends tcp probe every 60 seconds

If you want this available at boot time enter in the /etc/sysctl.conf 

net.ipv4.tcp_keepalive_time = 30